The logging industry is one area in which the use of manually encoded signals has evolved extensively. Such signals are known in the trade as whistle signals and are employed as a means of communication between workers in the field. As the name implies, the signals consist of predetermined sequences of long and short whistle blasts produced by a whistle, horn, or other audible signalling device. Typically, the audible signalling device is remotely actuated by radio-frequency (RF) signals from a manually actuated transmitter held by a worker. Each signal represents a specific instruction from one worker to another and usually pertains to the operation of a specific type of machinery. For example, standardized whistle signals are used to indicate a desired operation of yarding lines and associated yarders used in yarding operations.
In addition to communicating instructions from one worker to another, whistle signals serve an important safety function in alerting other workers in the vicinity of immediately impending changes in the operation of the machinery. In this regard, workers in the logging industry are cognizant of the standardized whistle signals and rely on such signals for forewarning of changes in the operation of the machinery. In recognition of this safety aspect of the use of whistle signals, various states and regulatory agencies have promulgated laws and regulations mandating the use of standardized whistle signals in logging operations.
In recent years the advantages of remote control systems, usually radio control systems, have become apparent in the logging industry. The advent of such systems has been complicated, however, by the necessity of adhering to the use of manually generated, standardized whistle signals for indicating the desired operations of logging machinery. Although there are various well known types of remote control systems that could be adapted to provide remote control of logging equipment, there has not been previously available a remote control system having a coding scheme based on standard whistle signals. In large part this is due to the fact that the whistle signals are manually generated and are thus subject to some variation from one worker to another, as well as variation in a given signal when produced at different times by an individual worker. For example, there may be significant variation in duration of the individual whistle blasts making up the signal, as well as variation in the durations of the intervening pauses, or spaces, between whistle blasts. Also, there may be a significant variation in the relative lengths of long and short whistle blasts, as well as variations in the relative durations of the intervening long and short spaces. Although such variation does not ordinarily pose any problem with respect to communication and understanding between workers in the field, who compensate for such variation as a matter of course, it has heretofore prevented the implementation of a remote control system having a coding scheme based on manually generated whistle signals.
Accordingly, it is an object and purpose of the present invention to provide an apparatus for utilizing manually encoded signals in a remote control system. More specifically, it is an object of the invention to provide an apparatus for utilizing manually encoded whistle signals in a remote control system for use in the logging industry.
It is also an object to achieve the foregoing objects in a remote control system wherein signals are manually encoded according to a predetermined coding scheme, and wherein such signals are decoded to execute predetermined control functions.
It is another object of the invention to provide a remote control system wherein manually encoded signals are decoded to execute predetermined control functions, and wherein the manually encoded signals are also utilized to produce audible signals that represent and serve to announce the control functions being executed.
These and other objects will be apparent on consideration of the ensuing description of the invention and the accompanying drawings.